towing cold iron

[bendorsey]

A year or so ago I asked the question on how do you build a fire in a cold steam locomotive. Got lots of interesting replies - many from former engineers and firemen who had done it many times.

Later I asked about banking the fire in a steam lcomotive for overnight and got another great bunch of interesting replies.

Heres another:

A while ago the FEC (Florida East Coast) railroad moved an 0-6-0 from Ft Lauderdale to Ft Pierce, Florida (about 120 miles). Supposedly it was capable of being fired up but they opted to tow it (and a few vintage railcars). When it went by the local beer-n-sudz joint (where else would you wait for a steam loco, lol) I noticed they had removed the connecting rods. I had several ideas as to why but I'll let the experts here provide the answers.

1. Why remove them?

2. Back when steam was king if a loco broke down and had to be towed would they remove them?

3. If not how difficult is it to tow a cold loco with them connected?

Ben

 

[cascaderailroad]

I would imaging that the pistons would have considerable resistance, if pushing a dead steamer, and things could bind, and break. Also a fire-able (uninspected/uncertified) loco could explode, and insurance costs would be high ... so they just tow it, deadheaded, with the connecting rods removed.

 

[bendorsey]

Yes - I thought of the resistence in the form of compressing the air in the cylinders until the control valves (piston or D slide depending on how old the loco is) opened to exhaust the air. Effectivly your running the system backwards to some extent. Some of that air exhausts into the smoke chest like normal but some goes into the boiler (I'd think) and if it does the pressure in the boiler might rise generating increased resistence (tho I'm not certain there isn't a way to prevent that).

Then theres the matter of lubrication. If its strictly mechanical it would be ok but if steam driven - not good.

Ben

 

[kws4000]

Then theres the matter of lubrication. If its strictly mechanical it would be ok but if steam driven - not good.

Ben

Absolutely - but even if the lube was mechanical, it still wouldn't help much because it still needs to be atomized in the steam to lubricate ALL surfaces. If they had a small fire and kept only 10-20psi and cracked the throttle while moving, then you could possibly do it with rods on. Same reason why you don't shut the throttle off while ghosting downgrade. EDIT: you would likely crack the throttle as well if you broke down, satisfying that other part of the question. If cold in the yards, then you'd probably take it slow and manually oil it frequently.

Oh, and if you're traveling on certain roads, the reciprocating weights inherent in steam locomotive "may damage the roadbed", so that's why they don't run tourist trains....

 

[bendorsey]

Yes - the VGN 2-10-10-2 was limited to about 15 MPH due to the massive amount of weight in reciprocating motion and thats under its own power. If running dead it might be worse since instead of the drivers pushing against the rails the rails are pushing against the drivers.

As for cracking the throttle a little that sounds worth a try but what if the breakdown was a massive steam leak and no steam pressure could be generated. I don't mean a boiler explosion - rather something like blowing a cylinder.

Ben

 

[wva-usa]

Yes - the VGN 2-10-10-2 was limited to about 15 MPH due to the massive amount of weight in reciprocating motion and thats under its own power. If running dead it might be worse since instead of the drivers pushing against the rails the rails are pushing against the drivers.

As for cracking the throttle a little that sounds worth a try but what if the breakdown was a massive steam leak and no steam pressure could be generated. I don't mean a boiler explosion - rather something like blowing a cylinder.

Ben

Cracking the throttle and drifting didn't fully address the problem on superheated locomotives and could result in carbonization of the lubrication largely because the drier superheated steam escaped more easily from the exhaust ports than saturated steam. Superheated steam could easily be above the flash point temps of most lubrication then in use. To solve the problem many locomotive were equipped with a (patented) drifting throttle that was a separate control.

RE: the VGN 2-10-10-2s

I've never read or hear anyone make much ado about the weight from the VGN 2-10-10-2 driver's rotation presenting any sort of problems. The typical top speed that usually quoted was about 15 MPH but that's because they were typically used in pusher service. Once they were replaced on the Clarks Gap grade by electric locomotive they were put into service on the Virginian "East End" where they were operated a faster speeds, apparently with no problems arising.

Being built later than most roads, the Virginian had larger clearances and being a coal hauling road it could handle heavier locomotives than the average rail line of the era could. But clearances (of the other roads) were a problem when it came time to deliver the locomotives. When new, each of the Virginian's 2-10-10-2 locomotives were delivered to the VGN from ALCO's Schenectady plant by being transported as "dead" engines, moved on their own wheels (but not under steam), with many of their external parts (including the huge front set of cylinders) being carried on a flat car, a box car and a gondola car.

 

[bendorsey]

According to the article on pages 36 and 37 of the August, 1967 issue of Model Railroader Magazine it was limited to approx 15 MPH by the forces caused by the gigantic low pressure cylinders (which I'd think qualifies as reciprocating motion).

Wish someone would make that loco for Trainz. The Santa Fe 2-10-10-2 is available as payware from PaulzTrainzUSA but the VGN 2-10-10-2 isn't available anywhere.

I also understand the tenders were rather short so the loco could be turned on existing 100 ft turntables.

Ben

 

[wva-usa]

According to the article on pages 36 and 37 of the August, 1967 issue of Model Railroader Magazine it was limited to approx 15 MPH by the forces caused by the gigantic low pressure cylinders (which I'd think qualifies as reciprocating motion).

Cylinders don't need to be operated under gigantic pressure downhill. Much of the VGN's line east of Princeton was either level, nearly level or downgrade. Trains would often reach speeds up to 25 MPH on those stretches, or so I've been told by real Virginian employees. But the 2-10-10-2 weren't used in these sections until they were bumped from their jobs by the VGN electrification in the mid-1920s.

Wish someone would make that loco for Trainz. The Santa Fe 2-10-10-2 is available as payware from PaulzTrainzUSA but the VGN 2-10-10-2 isn't available anywhere.

I also understand the tenders were rather short so the loco could be turned on existing 100 ft turntables.

Ben

Actually the 2-10-10-2 were rarely turned on a turntable when they were doing the job they were built for, which was serving as pushers on the Clarks Gap grade. Their home base was Elmore, where there was no turntable. They were turned on a wye by a hostler. There wasn't enough spare, flat land for a turntable at Elmore, which is surrounded by hills on all sides (pic below -- the branches of the wye track ran behind the enginehouse and on the right and left sides of it). The VGN had to divert the Guyandotte River to gain enough flat land to build the enginehouse and coaling station.



The 2-10-10-2 pushers would cut off at the summit, then backed down the grade, returning to their home terminal at Elmore. A 2-8-8-2 would take the train into Princeton.

In their regular revenue service they rarely were run as far east as Princeton, which was the nearest terminal that had a turntable. About the only time a 2-10-10-2 would go to Princeton would be for major servicing, as Princeton was where the VGN main service shop was located.

All of the Virginian's pushers featured short tenders, in the 12,000 to 13,000 gallon range. Using short tenders on pushers made good economical sense, which is why the Virginian and many (most?) other railroads used tenders on pushers that were only as big as necessary. Why lug around needless weight?

 

[bendorsey]

Interesting.

Sounds like this is one of your favorite roads (considering the name in your siggy, lol).

Ben

 

[smash]

WVA-USA,
Thanks for the history lesson.
Kenny

 

[wva-usa]

Interesting.

Sounds like this is one of your favorite roads (considering the name in your siggy, lol).

Ben

My dad was a fireman on the Virginian so I never had the option of not liking the VGN. A half-a-dozen or so relatives on my mom's side of the family worked for the C&O. I think I was about 4 before I realized that there were people in the world who talked about things other than railroads.


RE: The towing of dead steam locos

Here's what a book printed in 1911, Locomotive Breakdowns: Emergencies and Their Remedies, had to say on the subject:

Q: How should a dead locomotive be disconnected for towing?

A: The generally accepted method of disconnecting an engine for towing is to take down the main rods block the crossheads and clamp the valve stems leaving all of the side rods in position if possible.

The reason for leaving the side rods in place is that they serve to balance the cranks and thus neutralize the hammerblow that would otherwise be delivered to the rail by the unbalanced crank. This corresponds with the condition in which new engines are put when being towed from the shops of the builder to the purchaser and whose speed of movement over the road is usually limited a rule which must be observed in the towing of a dead engine.

If however the condition of the engine is such as to necessitate the removal of any of the side rods it should be borne in mind that the corresponding ones upon the other side of the engine must be removed also.

These directions for disconnecting an engine will have to be modified in many instances dependent upon the nature of the accident which the engine has suffered and the condition of other parts. It is evident therefore that no general directions can be given that will cover every specific case but that the treatment of each must be distinct and referred to the judgment of the engineer in charge.

WVA-USA,
Thanks for the history lesson.
Kenny

Thanks, Kenny. Recounting history is one of the things on my "bucket list".

 

[bendorsey]

Ditto thanks for the history lesson. Quite interesting.

Heres a weird thought (I have them often, lol).

If the mains were left connected wouldn't the pistons be pumping air? Possibly from the smoke stack into the boiler? I know that sound crazy but isn't it a sealed system except for the stack?

Ben

 

[kws4000]

Ditto thanks for the history lesson. Quite interesting.

Heres a weird thought (I have them often, lol).

If the mains were left connected wouldn't the pistons be pumping air? Possibly from the smoke stack into the boiler? I know that sound crazy but isn't it a sealed system except for the stack?

Ben

Snifting valves: http://en.wikipedia.org/wiki/Snifting_valve

also: open the cylinder cocks (like when starting)

 

[wva-usa]

Snifting valves: http://en.wikipedia.org/wiki/Snifting_valve

also: open the cylinder cocks (like when starting)

Snifting valves were used on some older American steam, and on European locos, but most of the modern American locomotives used by-pass/relief valves, which provided the same benefits of a snifting valve, while also keeping the cylinders lubricated when the throttle was shut.

There's an article on the by-pass and drifting valves that can be read here -- at Google Books.

The N&W Historical Society has a page about by-pass valves, that has a diagram illustrating how they worked, that can be viewed here. This article also provide a bit of info about vacuum valves, which admitted free air into the steam chests when drifting, thus avoiding a vacuum and providing a moderate flow of air through the cylinders.

 

[bendorsey]

I thought about the cylinder cocks but had never heard of the other two. Quite interesting. Thanks.

Mention steam locos to most folks and they immediately equate them with dinosaurs but theres a heck of a lot of sophisticated technology in a steam engine.

Ben

 

[Konni]

Hi,

To be precise, for towing a cold steam locomotive over longer distances the connecting rods between the crossheads and the drive wheels are removed. The connecting rods between the drive wheels and the other wheels are normally kept.


The reason is to reduce internal friction and to avoid lubrication problems between cylinders and pistons. There are several reasons for this:

1. the oil used for lubrication of cylinders is designed to operate at steam temperatures. at ambient temperatures it will not work properly.

2. With some locomotives the lubricator pump worked only if the boiler was producing steam

3. Whether the steam cylinders of a locomotive can also be made to work as compressors depends upon the design of the steam valves.
Clamshell valves would only lift from their seats if the steam was turned off, e.g. when rolling downhill. Except for the internal mechanical friction they would not produce any braking power. Older cylinder valves needed sniffing valves and/or connecting valves to prevent the steam cylinders to act like compressors when the locomotive was pulled or simply rolling down downhill. More modern designs of cylinder valves e.g. by Trofimoff would open automatically in such a way as to allow steam to move through the valve from one side of the piston to the other if steam was turned off.

Normally compression work by steam cylinders is undesirable. However, the Swiss locomotive designer Niklaus Riggenbach invented a set of additional valves, by which the steam cylinders can be made to work as air compressors. Air is sucked in, compressed by the steam cylinders and released by reduction valves back into the air. The brake power generated by the air compression acts on the wheels and requires no brake blocks. This prevents brake blocks to overheat and reduces mechanical wear on brake blocks and wheel tyres when running downhill over longer distances. Many locomotives working on mountain routes are therefore fitted with Riggenbach brakes. The locomotives using Riggenbach brakes have to be equipped with cylinder valves, where the sniffing and connecting valves may be turned off.
Since braking power generated can be calculated precisely from the cylinder diameter, stroke and compression, locomotives equipped with Riggenbach brakes were retained for determining locomotive power experimentally, sometimes even beyond the end of regular steam operation.

4. Avoidance of internal friction in the steam cylinders and valve gear which would cause stress to parts of the valve gear.

By the way: During the 19th century locomotives were also braked by putting the reverser into reverse and leaving the steam on. Since this braking method puts considerable stress on the entire steam engine, it was banned as locomotives increased in power.

With old locomotives, rescued from a scrap yard or from decaying in the open as monuments, the entire steam engine is most likely so badly rusted up, that friction would increase dramatically when the locomotive is towed.

The speed by which the locomotive can be towed depends upon several factors:

1. If the boiler can be fired and the locomotive's cylinder lubrication system made to work, it can be towed at speeds within the loco's permissible speed range. This happens occasionally if a steam locomotive is towed by diesel or electric locomotive from one museum railway to another.
2. If the connecting rods between crossheads and drive wheels are removed there is some imbalance on the drive wheels, requiring a speed reduction.
3. If all connecting rods are removed, imbalance increases requiring even stronger speed reductions.

4. An important factor is whether the locomotives compressed air brakes are usable. If yes they can be supplied with compressed air from the towing locomotive and the brakes operated from that locomotive. If no, then there may ba a 100 to unbraked mass to handle safely. The only way to do this is to tow cautiously at a snail's pace.

Cheers,

Konni

 

[wva-usa]

... Normally compression work by steam cylinders is undesirable. However, the Swiss locomotive designer Niklaus Riggenbach invented a set of additional valves, by which the steam cylinders can be made to work as air compressors. Air is sucked in, compressed by the steam cylinders and released by reduction valves back into the air. The brake power generated by the air compression acts on the wheels and requires no brake blocks. This prevents brake blocks to overheat and reduces mechanical wear on brake blocks and wheel tyres when running downhill over longer distances. Many locomotives working on mountain routes are therefore fitted with Riggenbach brakes. The locomotives using Riggenbach brakes have to be equipped with cylinder valves, where the sniffing and connecting valves may be turned off.
Since braking power generated can be calculated precisely from the cylinder diameter, stroke and compression, locomotives equipped with Riggenbach brakes were retained for determining locomotive power experimentally, sometimes even beyond the end of regular steam operation.

Riggenbach's braking system was a type of counter-pressure brake. There was also a Le Chatelier counter-pressure brake. Both are a types of dynamic brakes. I can't recall ever reading about either system ever being used in North America, but perhaps some NA rack railway systems used them. If I remember correctly both were limited to use only at slower speeds, maybe 20 MPH or less.

Le Chatelier published a book on the subject in 1869, Railway Economy: Use of Counter-Pressure Steam in the Locomotive Engine as a Brake, that can be read at Google Books.

Interestingly enough, counter-pressure brakes are among the features to be incorporated on the CSR Project 130 locomotive, a project by the Coalition for Sustainable Rail (CSR) to design of a prototype 130 MPH steam passenger locomotive for the 21st century,


Edited to add this: After doing a quick search online, it seems the Mount Washington rack railroad in New Hampshire made use of counter-pressure brakes. (Perhaps they still do?)